There is a bug floating around and you might be seeing it. Please log a call with Symantec and refer to Etrack – 2914202 to verify.

From what they can tell EV appears to be failing to read the size attribute of a SIS part during post processing which results in an Invalid SIS part error being encountered. There is no evidence of data loss and from the tests that have been done - dump saveset retruns the item in its entirety.